| Cytochrome c', a soluble c-type protein found in the periplasmic space of many bacteria, has been purified from Rhodobacter sphaeroides 2.4.1 through two separate methods. Although both techniques allowed for the successful purification of cytochrome c', method 2 proved to be the most effective approach yielding twice the amount of protein as method 1. The UV/visible absorption spectra of purified cytochrome c' was determined and exhibited a pH dependent transition (between pH 4-pH 7) typical of most c-type cytochromes. Molecular dynamics simulations were performed in order to study the dynamics of the solvent accessible channel in cytochromes c' and its function in the binding properties of these proteins. Simulations were performed using cytochrome c' crystal structures from Rhodobacter capsulatus, Rhodobacter sphaeroides, Chromatium vinosum, and Rhodospirillum molischianum as models. Contrary to previous crystallographic data, evidence from these simulations suggests Rhodobacter capsulatus cytochrome c' lacks the presence of a solvent accessible channel in solution similar to other group 2 cytochromes c'. These findings suggest that it is not only the amino acid composition of helices B and C that determine the size and presence of the solvent accessible channel, but also their dynamics in solution. |
